INTEGRATED INTERPOSER SOLUTIONS FOR 2D AND 3D IC PACKAGING
An integrated circuit (IC) package includes a first substrate having a backside surface and a top surface with a cavity disposed therein. The cavity has a floor defining a front side surface. A plurality of first electroconductive contacts are disposed on the front side surface, and a plurality of second electroconductive contacts are disposed on the back side surface. A plurality of first electroconductive elements penetrate through the first substrate and couple selected ones of the first and second electroconductive contacts to each other. A first die containing an IC is electroconductively coupled to corresponding ones of the first electroconductive contacts. A second substrate has a bottom surface that is sealingly attached to the top surface of the first substrate, and a dielectric material is disposed in the cavity so as to encapsulate the first die.
This application claims the benefit of U.S. Provisional Application No. 62/007,758, filed Jun. 4, 2014, the entire disclosure of which is incorporated herein by reference.
BACKGROUND1. Technical Field
This application relates to integrated circuit (IC) packages and wafer scale methods for making them in general, and in particular, to making two-dimensional (2D) and three-dimensional (3D) IC packages using integrated interposers (ITPs).
2. Related Art
In recent years, the size of semiconductor chips has shrunk dramatically in order to achieve a number of performance goals, e.g., higher signal propagation, lower power consumption, lower fabrication costs, and reduced form factors, among others. As the semiconductor industry has struggled to pack more functionality into smaller and smaller spaces, some have suggested that, without new ground-breaking technologies in processing and assembly, the well-known “Moore's law,” i.e., that the number of transistors in densely integrated circuits doubles approximately every two years over the history of computing hardware, may cease to hold true. Vertical integration, i.e., three-dimensional integrated circuit (“3D IC” or “3D”) packaging, has emerged as one of the more promising technology to achieve the above goals.
However, 3D IC packaging presents designers and fabricators with a number of challenges. For example, a current trend in 3D IC assembly is to assemble microbumped dies onto thin interposers (ITPs). However, fabrication and assembly of relatively thin ITPs can create a number of problems. One is that, in order to thin the ITP down to the desired thickness, the ITP wafer is typically mounted on a “carrier” with temporary adhesives, typically low-melting-temperature polymers, during the thinning and subsequent processing. The relatively low melting temperatures of the adhesives limit the overall maximum temperatures that can be used in so-called “backside” processing. Wafer breakage is also increased during the demounting process and associated wafer handling. Another problem is a warpage issue that can occur during assembly in that, not only it is it very difficult to connect microbumps to a warped ITP die, but the warpage also creates a long term reliability issue by imposing stresses on solder bumps and functional dies.
Accordingly, a long felt but as yet unsatisfied need exists for 2D and 3D IC designs and manufacturing methods that overcome the foregoing and other problems of the prior art.
SUMMARYIn accordance with embodiments of the present disclosure, novel 2D and 3D IC packages using integrated ITPs are provided, together with methods for making them.
In one example embodiment, a 2D IC package comprises a first substrate having a backside surface and a top surface with a cavity disposed therein. The cavity has a floor defining a front side surface. A plurality of first electroconductive contacts are disposed on the front side surface, and a plurality of second electroconductive contacts are disposed on the back side surface. A plurality of first electroconductive elements penetrate through the first substrate and couple selected ones of the first and second electroconductive contacts to each other. A first die containing an IC is electroconductively coupled to corresponding ones of the first electroconductive contacts. A second substrate has a bottom surface that is sealingly attached to the top surface of the first substrate, and a dielectric material is disposed in the cavity so as to encapsulate the first die. The dielectric material can comprise an inorganic material.
In another example embodiment, the foregoing 2D IC package can be used as a foundation for making a 3D IC package comprising a plurality of third electroconductive contacts disposed on a top surface of the first die, a plurality of fourth electroconductive contacts disposed on a top surface of the second substrate, and a plurality of second electroconductive elements penetrating through the second substrate and coupling selected ones of the third and fourth electroconductive contacts to each other. A second die containing an IC is electroconductively coupled to corresponding ones of the fourth electroconductive contacts, and a cover having a bottom surface is sealingly attached to the top surface of the second substrate so as to enclose the second die.
The scope of this invention is defined by the claims appended hereafter, which are incorporated into this section by reference. A more complete understanding of the features and advantages of the novel methods for fabricating novel 2D and 3D IC packages using integrated ITPs will be afforded to those of some skill in the art by a consideration of the detailed description of some example embodiments thereof presented below, especially if such consideration is made in conjunction with the figures of the appended drawings briefly described below, wherein like reference numerals are used to identify like elements illustrated in one or more of the figures thereof.
In accordance with the present disclosure, example embodiments of 2D and 3D integrated circuit packages are provided, together with methods for making them using integrated ITPs.
“Wafer level” or “wafer scale” production of integrated circuit (IC) packages has proliferated in recent years, due primarily to the economies of scale that such production techniques afford, together with a concomitant reduction in size and cost of the resulting packages. Examples of such IC packages and methods for making them can be found in, e.g., commonly owned U.S. patent application Ser. No. 14/214,365 by H. Shen, et al., filed Mar. 14, 2014, and entitled “Integrated Circuits Protected by Substrates with Cavities, and Methods of Manufacture,” the entire disclosure of which is incorporated herein by reference.
In only one of many possible embodiments, such packages can be cut, or “singulated” from a wafer or a sandwich of two or more aligned wafers containing a number of similar packages, and can include a portion of at least one wiring substrate wafer, sometimes referred to as an “interposer” (ITP) wafer, having an upper surface upon which are mounted one or more semiconductor dies, chips or stacked dies (which can be packaged or unpackaged), each containing one or more integrated circuits (ICs). The ITP can contain a pattern of electroconductive traces, e.g., in the form of a “redistribution layer” (RDL), on its upper surface, its lower surface, and/or intermediate its upper and lower surfaces, to which the ICs are variously electroconductively connected to each other and/or other components. The ITP can also mount and/or contain discrete passive electrical components, such as resistors, capacitors, inductors, or the like, that are disposed either on its surface or within its thickness, as described in, e.g., commonly owned U.S. patent application Ser. No. 14/268,899 by L. Wang, et al., filed May 2, 2014, and Ser. No. 14/304,535 by L. Wang, et al., filed Jun. 13, 2014, the entire disclosure of each of which is incorporated herein by reference.
Silicon ITPs, using through-silicon “vias” (TSVs) can become a key component of the 3D IC technology evolution, in which dies are stacked and electroconductively connected vertically to function as a single device. A typical TSV fabrication process can involve a deep reactive ion etching of a through-hole, or “via” in a silicon wafer, chemical vapor deposition (CVD) or physical vapor deposition (PVD) of barrier and seed layers inside the via, and electrochemical deposition (ECD) of e.g., copper (Cu), tungsten (W) or polycrystalline silicon (polysilicon) to fill the via with an electroconductive material.
To increase the speed of packaged devices, signal transmission lines must be made very short. The current trend in 3D IC assembly is to assemble microbumped dies onto thin ITPs, e.g., in the range of 25-100 microns or micrometers (μm) (1 μm=1×106 meters) in thickness. However, fabrication and assembly of such thin ITPs can create several problems. One is that, in order to thin the ITP down to the desired thickness, the ITP wafer is typically mounted on a carrier with a temporary adhesive, typically low-melting-temperature polymers, during the thinning and subsequent processing. The low melting temperatures of the adhesives disadvantageously limit the overall temperatures that can be used in backside processing. The likelihood of wafer breakage is also increased during the demounting process and subsequent wafer handling. Another problem that can occur with thin ITPs is a warpage issue during assembly in that, not only is it very difficult to connect microbumps on a warped ITP die, the warpage also creates long term reliability issues by imposing stresses on solder bumps and functional dies during use.
Through research and development, it has been discovered that the thin-wafer handling and warpage issues above can be successfully resolved by the utilization of a carrier wafer in which, unlike the temporary carrier used in the conventional process, the carrier wafer (or an associated portion of it) becomes an integral part of the mechanical structure of the end IC packages. Thus, functional dies are attached to a full-thickness ITP wafer. Using wafer-to-wafer bonding, the carrier wafer, or an associated portion of it, is permanently attached to the ITP to fully enclose the functional dies. The carrier wafer provides the necessary support and structure during the subsequent thinning processes of the ITP wafer, without the need to mount the wafer to a carrier wafer using a low-melting-temperature adhesive. The carrier wafer and the ITP wafer are thermally matched such that, after processing, there is little or no stress resulting from a mis-match in the respective coefficients of thermal expansion (CTEs) of the carrier and ITP wafers, in contrast to conventional die attach and molding processes.
In accordance with the foregoing,
The wafer can comprise a wide variety of suitable materials, including semiconductor materials, e.g., monocrystalline silicon, which is amenable to well-known photolithography manufacturing techniques and has a CTE matched to that of, e.g., one or more silicon IC dies that are attached to it. Alternatively or additionally, other materials, such as glass, metal, or other suitable material, can be utilized or incorporated.
As illustrated in
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As those of some skill will appreciate, the second substrate 28 need not necessarily comprise a portion of a second wafer. Thus, in an alternative embodiment, the layer 26 of bonding material can be omitted, and the second substrate 28 can instead comprise a layer of a polymer, e.g., an epoxy resin, that is molded over the planarized top surfaces of the first substrate 10, die 20 and bonding material 24, or in yet other embodiments, could comprise a TIM layer or a metal layer.
As illustrated in
If no other thinning processes are to be applied, then as illustrated in
However, if it is desired to thin the end IC package 38 further, one or more of the foregoing “back side” processes and corresponding features can be delayed in favor of a top side thinning operation similar to that applied to back side surface 30 of the first substrate 10 described above in connection with
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Following this step, a layer 50 of a bonding material, e.g., a layer of an oxide, e.g., SiO2, a metal, BCB, TIM, an adhesive, glass frit, or the like, can be deposited onto the top surface 40 of the second substrate 28, in a manner similar to that discussed above in connection with
In the particular example 3D IC package 56 illustrated in
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As those of some skill will recognize, the embodiment of
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And as above, the third substrate 128 need not necessarily comprise a portion of a third wafer. Thus, in an alternative embodiment, the layer 126 of bonding material can be omitted, and the second substrate 128 can instead comprise a layer of glass, a polymer, e.g., an epoxy resin, or a metal that is molded, formed or bonded over the planarized top surfaces of the second substrate 108, first die 20, and the bonding material 124.
As illustrated in
If no other thinning processes are to be applied, then as illustrated in
As those of some skill will recognize, except for the “window frame” second wafer 108 used to define the first cavity 116, the 2D IC package 134 of
In light of the foregoing detailed description, it should be clear to those of some skill in this art that many modifications, substitutions and variations can be made in and to the methods and materials of the IC packages with integrated ITPs of the present disclosure, and accordingly, that the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.
Claims
1. An integrated circuit (IC) package, comprising:
- a first substrate having a backside surface and a top surface with a cavity disposed therein, the cavity having a floor defining a front side surface;
- a plurality of first electroconductive contacts disposed on the front side surface;
- a plurality of second electroconductive contacts disposed on the back side surface;
- a plurality of first electroconductive elements penetrating through the first substrate and coupling selected ones of the first and second electroconductive contacts to each other;
- a first die containing an IC electroconductively coupled to corresponding ones of the first electroconductive contacts;
- a second substrate having a bottom surface sealingly attached to the top surface of the first substrate; and
- a dielectric material disposed in the cavity and encapsulating the first die.
2. The IC package of claim 1, further comprising:
- a plurality of third electroconductive contacts disposed on a top surface of the first die;
- a plurality of fourth electroconductive contacts disposed on a top surface of the second substrate;
- a plurality of second electroconductive elements penetrating through the second substrate and coupling selected ones of the third and fourth electroconductive contacts to each other;
- a second die containing an IC electroconductively coupled to corresponding ones of the fourth electroconductive contacts; and
- a cover having a bottom surface sealingly attached to the top surface of the second substrate and enclosing the second die.
3. The IC package of claim 2, wherein the cover comprises a polymer molded over the top surface of the second substrate and encapsulating the second die.
4. The IC package of claim 2, wherein the cover comprises:
- a third substrate having a bottom surface with a cavity disposed therein, the bottom surface being sealingly attached to the top surface of the second substrate such that the second die is disposed within the cavity; and
- a dielectric material disposed within the cavity and encapsulating the second die.
5. The IC package of claim 4, wherein the dielectric material comprises an inorganic material.
6. The IC package of claim 4, wherein at least one of the first, second and/or third substrates comprises a semiconductor.
7. The IC package of claim 2, further comprising an electroconductive redistribution layer (RDL) disposed on at least one of the front side surface of the first substrate, the back side surface of the first substrate and/or the top surface of the second substrate and coupling selected ones of the electroconductive contacts respectively disposed thereon to each other.
8. The IC package of claim 2, wherein at least one of the electroconductive elements penetrating through the first and second substrates comprises a through-silicon via (TSV).
9. The IC package of claim 2, wherein at least one of the first and second dies is electroconductively coupled to the corresponding ones of the electroconductive contacts by solder bumps.
10. The IC package of claim 2, wherein the first die, the second die or both the first and the second die comprises a plurality of dies.
11. A method for making an integrated circuit (IC) package, the method comprising:
- providing a first substrate having a backside surface, a top surface and a cavity disposed in the top surface, the cavity having a floor defining a front side surface;
- forming electroconductive contacts on respective ones of the front and back side surfaces;
- forming a plurality of electroconductive elements penetrating through the first substrate and interconnecting selected ones of the electroconductive contacts respectively disposed on the front and back side surfaces to each other;
- disposing a first die containing an IC within the cavity and eleetroconductively coupling it to corresponding ones of the electroconductive contacts disposed on the front side surface;
- sealingly attaching a bottom surface of a second substrate to the top surface of the first substrate; and
- injecting a dielectric material into the cavity so as to encapsulate the first die.
12. The method of claim 11, further comprising etching a top surface of the first die and the top surface of the first substrate to reduce a final thickness of the IC package.
13. The method of claim 11, further comprising:
- coupling the back side surface of the first substrate to a wafer chuck; and
- grinding top surfaces of the dielectric material, the die and the first substrate to make them coplanar with each other and to reduce a final thickness of the IC package.
14. The method of claim 11, further comprising:
- coupling a top surface of the second substrate to a wafer chuck; and
- grinding the back side surface of the first substrate to reduce a final thickness of the IC package.
15. The method of claim 11, wherein the forming of the electroconductive elements comprises reactive ion etching (RIE).
16. An integrated circuit (IC) package, comprising:
- a first substrate having a backside surface and a front side surface;
- a plurality of electroconductive elements penetrating through the first substrate and coupling selected ones of electroconductive contacts respectively disposed on the front side surface and the back side surface to each other;
- at least one first die containing an IC electroconductively coupled to corresponding ones of the electroconductive elements disposed on the front side surface;
- a second substrate having a bottom surface sealingly attached to the front side surface of the first substrate and a through-opening surrounding the first die;
- a third substrate having a bottom surface sealingly attached to a top surface of the second substrate, the bottom surface and the through-opening defining a first cavity enclosing the first die, and
- a dielectric material disposed within the first cavity and encapsulating the at least one first die.
17. The IC package of claim 16, further comprising:
- a plurality of electroconductive elements penetrating through the third substrate and coupling selected ones of electroconductive contacts respectively disposed on a top surface of the at least one first die and a top surface of the third substrate to each other;
- at least one second die containing an IC electroconductively coupled to corresponding ones of the electroconductive contacts disposed on the top surface of the third substrate; and
- a dielectric material encapsulating the at least one second die.
18. The IC package of claim 17, wherein
- the third substrate includes a second cavity in the bottom surface thereof, and
- the at least one second die and the dielectric material are disposed within the second cavity.
19. The IC package of claim 18, wherein the dielectric material comprises an inorganic material.
20. The IC package of claim 17, further comprising an electroconductive redistribution layer (RDL) disposed on at least one of the front side surface of the first substrate, the back side surface of the first substrate and/or the top surface of the third substrate and coupling selected ones of the electroconductive contacts respectively disposed thereon to each other.
21. The IC package of claim 17, wherein at least one of the at least one first die and the at least one second die is electroconductively coupled to the corresponding ones of the electroconductive contacts by solder bumps.
22. An integrated circuit (IC) package, comprising:
- a first substrate having a back side surface and a front side surface, each of the back side and front side surfaces having an associated plurality of electroconductive contacts respectively disposed thereon;
- a plurality of electroconductive elements penetrating through the first substrate and coupling selected ones of the associated electroconductive contacts respectively disposed on the front side surface and the back side surface to each other;
- a first die containing an IC electroconductively coupled to corresponding ones of the electroconductive contacts disposed on the front side surface;
- a second substrate having a cavity disposed in a bottom surface thereof, the bottom surface being sealingly attached to the front side surface of the first substrate such that the cavity encloses the first die; and
- a dielectric material disposed in the cavity and encapsulating the first die.
23. The IC package of claim 22, further comprising an electroconductive redistribution layer (RDL) disposed on the front side surface of the first substrate and coupling selected ones of the electroconductive contacts disposed thereon to each other.
24. The IC package of claim 22, wherein the dielectric material comprises an inorganic material.
Type: Application
Filed: Dec 30, 2014
Publication Date: Dec 10, 2015
Patent Grant number: 9741649
Inventors: Hong Shen (Palo Alto, CA), Charles G. Woychik (San Jose, CA), Arkalgud R. Sitaram (Cupertino, CA), Guilian Gao (San Jose, CA)
Application Number: 14/586,580